lix/src/archive.cc

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#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <dirent.h>
#include <fcntl.h>
#include "archive.hh"
#include "util.hh"
static void pad(unsigned int len, DumpSink & sink)
{
if (len % 8) {
unsigned char zero[8];
memset(zero, 0, sizeof(zero));
sink(zero, 8 - (len % 8));
}
}
static void writeInt(unsigned int n, DumpSink & sink)
{
unsigned char buf[8];
memset(buf, 0, sizeof(buf));
buf[0] = n & 0xff;
buf[1] = (n >> 8) & 0xff;
buf[2] = (n >> 16) & 0xff;
buf[3] = (n >> 24) & 0xff;
sink(buf, sizeof(buf));
}
static void writeString(const string & s, DumpSink & sink)
{
unsigned int len = s.length();
writeInt(len, sink);
sink((const unsigned char *) s.c_str(), len);
pad(len, sink);
}
static void dumpEntries(const string & path, DumpSink & sink)
{
DIR * dir = opendir(path.c_str());
if (!dir) throw SysError("opening directory " + path);
Strings names;
struct dirent * dirent;
while (errno = 0, dirent = readdir(dir)) {
string name = dirent->d_name;
if (name == "." || name == "..") continue;
names.push_back(name);
}
if (errno) throw SysError("reading directory " + path);
sort(names.begin(), names.end());
for (Strings::iterator it = names.begin();
it != names.end(); it++)
{
writeString("entry", sink);
writeString("(", sink);
writeString("name", sink);
writeString(*it, sink);
writeString("file", sink);
dumpPath(path + "/" + *it, sink);
writeString(")", sink);
}
closedir(dir); /* !!! close on exception */
}
static void dumpContents(const string & path, unsigned int size,
DumpSink & sink)
{
writeString("contents", sink);
writeInt(size, sink);
int fd = open(path.c_str(), O_RDONLY);
if (!fd) throw SysError("opening file " + path);
unsigned char buf[65536];
unsigned int total = 0;
ssize_t n;
while ((n = read(fd, buf, sizeof(buf)))) {
if (n == -1) throw SysError("reading file " + path);
total += n;
sink(buf, n);
}
if (total != size)
throw SysError("file changed while reading it: " + path);
pad(size, sink);
close(fd); /* !!! close on exception */
}
void dumpPath(const string & path, DumpSink & sink)
{
struct stat st;
if (lstat(path.c_str(), &st))
throw SysError("getting attributes of path " + path);
writeString("(", sink);
if (S_ISREG(st.st_mode)) {
writeString("type", sink);
writeString("regular", sink);
dumpContents(path, st.st_size, sink);
}
else if (S_ISDIR(st.st_mode)) {
writeString("type", sink);
writeString("directory", sink);
dumpEntries(path, sink);
}
else if (S_ISLNK(st.st_mode)) {
writeString("type", sink);
writeString("symlink", sink);
char buf[st.st_size];
if (readlink(path.c_str(), buf, st.st_size) != st.st_size)
throw SysError("reading symbolic link " + path);
writeString("target", sink);
writeString(string(buf, st.st_size), sink);
}
else throw Error("unknown file type: " + path);
writeString(")", sink);
}